How much storage does video recording use?
Quick answer
Video storage depends on bitrate, not resolution alone: GB = bitrate (Mbps) x seconds / 8 / 1000. One hour at 8 Mbps is 3.6 GB; one hour at 50 Mbps is 22.5 GB.
- 1Find the bitrate your camera or app actually uses, not just the resolution label.
- 2Multiply bitrate (Mbps) by duration in seconds.
- 3Divide by 8, then by 1,000, to get GB.
- 4Multiply by the number of cameras recording at once, if more than one.
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Resolution alone does not determine file size - bitrate does. Two 4K recordings can differ enormously in size if one uses a much higher bitrate than the other, which is why "how much storage does 4K use" has no single answer without knowing the bitrate.
The formula is simple once you have the bitrate: GB = bitrate in Mbps x duration in seconds, divided by 8 (to convert bits to bytes) and then by 1,000 (to convert MB to GB). Typical ballpark bitrates: 1080p at 30fps is roughly 8-15 Mbps, 4K at 30fps roughly 25-60 Mbps, 4K at 60fps roughly 50-100+ Mbps, and 8K is 100 Mbps and well above - these vary by device, codec and settings, so check your own camera's actual setting rather than assuming a figure from its resolution label.
Storage per hour at common bitrates
| Bitrate | GB per minute | GB per hour |
|---|---|---|
| 8 Mbps | 0.06 | 3.6 |
| 25 Mbps | 0.19 | 11.25 |
| 50 Mbps | 0.38 | 22.5 |
| 100 Mbps | 0.75 | 45 |
Step by step
Check the bitrate setting
Look in your camera or app's settings, not just the resolution label - this is what actually determines file size.
Multiply by camera count if recording multiple feeds
Total storage scales directly with the number of cameras recording at once.
Video Storage CalculatorWork out recording time for a fixed card or drive
Rearrange the same formula to find how long a given capacity lasts at your bitrate.
Video Storage Calculator
Tips
- Check the bitrate in your camera or app settings, not just the resolution label.
- H.265 (HEVC) often gives similar quality at a lower bitrate than H.264, which saves space.
- Leave 10 to 20 percent free space on any card or drive for safety.
- For editing, remember you need space for the original files, proxies and the exported result.
Common problems
My real file is much bigger or smaller than the estimate.
Cameras use variable bitrates. Static scenes compress better than fast motion, so treat the estimate as an average, not an exact figure.
The card says it holds more than I calculated.
Card makers use decimal GB (1 GB = 1,000 MB) while some devices report binary GB, so the gap can be around 7 percent.
Examples
A 3-hour 4K recording at 50 Mbps
50 Mbps x 3 hours x 3,600 / 8 / 1,000 = 67.5 GB. A 128 GB card would hold roughly 5 hours at this bitrate, allowing for some headroom.
Frequently asked questions
- How many GB is one hour of 4K video?
- Roughly 10 to 25 GB at typical consumer bitrates, but it depends on the bitrate your camera or app uses. Higher quality settings can use much more.
- How do I calculate video file size?
- File size in GB = bitrate in Mbps x duration in seconds / 8 / 1000.
- Does frame rate change file size?
- Usually yes, because higher frame rates normally use a higher bitrate. 60 fps footage is often noticeably larger than 30 fps.
Related related tools
- Video Storage CalculatorPick a resolution and duration (or a storage size) and see the other side of the equation.
- Video Recording Time CalculatorTurn free storage and a bitrate into recording time - with every step of the formula shown.
- 4K Video Storage CalculatorPlan storage for a 4K shoot: per hour, per day, per week and per month, across every camera.
- 8K Video Storage CalculatorWork out how many terabytes an 8K shoot needs - per hour, per day and across the whole project.
- SD Card Recording Time CalculatorFind out how long you can record on an SD or microSD card at your camera’s bitrate.
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